Although low back pain is the United States' sixth most expensive condition, and one-half of all outpatient physical therapy (PT) visits are for its treatment, we lack a clear understanding of organizational level and service delivery factors related to quality of PT care for this population. While profiling performance of physicians, managed care providers, and inpatient hospitals has been used over the past decade to understand factors related to provider performance, no prior studies have profiled outpatient physical therapy clinics. Our specific aims are to: 1) Profile PT clinics by quality of care for patients with lumbar spine syndromes; 2) Quantify the relationship between staffing and caseload characteristics and the quality profile that we develop, 3) Quantify the relationship between clinic quality profile and service utilization patterns. We will use data from 17,710 patients with low back pain treated at 114 outpatient PT clinics tracked by the Focus On Therapeutic Outcomes Inc. (FOTO) database in 2000-2001. FOTO contains patient demographic, health-related quality of life (HRQL) and administrative data, as well as data on characteristics of therapists and clinics. We will profile clinics' quality of care (operationalized as HRQL measured at discharge) estimated using a 3-level model in which patients are nested within therapists, and therapists nested within clinics. The relationship between clinic profile and independent variables related to clinic staffing, caseload and service utilization patterns will be examined. This research will provide important, new information on organizational level and utilization factors related to quality of care for patients with low back pain, and insight into the application and development of profiling methods for studying outpatient rehabilitation clinics. Findings from this study will guide a future systematic data collection and comprehensive analysis effort that will lead to quality improvement initiatives. Ultimately, the information from this series of studies may be used to shape the policy regarding regulation and administration of rehabilitative services.